Issue
Unable to delete an Encrypted Field Configuration
Cause
There is a step missing from the documentation that states that the field type must be changed in the field's dictionary record from Encrypted Text to String before the Encrypted Field Configuration record can be deleted.
Resolution
Change the field type in the dictionary record from Encrypted Text to String and then you will be able to delete the Encrypted Field Configuration record. In your case, since you have already deleted the field you will need to temporarily deactivate the table-level "delete" operation ACL for the sys_platform_encryption_configuration table, delete the Encrypted Field Configuration record and reactivate the ACL.
